Portraying the late actress, Williams reveals she has immersed herself so deeply in interpreting Monroe. "I feel like we live together. At a certain point, something else does take over. I don't quite feel myself these days," she tells the site.

However, the blonde actress admits she was initially terrified of taking the role. "I knew I wouldn't be able to resist, eventually. Physically and vocally, everything about her is different from me," she opens up. "I've kind of gone to school and had teachers to help me understand Marilyn, so I could project an essence of her. When I first approached the part, I thought that there were three, even four parts to Marilyn."

The film, based on the diary of Colin Clark, chronicles a week in the life of Marilyn Monroe in which she escapes the shackles of her Hollywood career and embraces British life with Clark. Clark himself was Sir Laurence Olivier's employee who looked after Monroe when she arrived in London to film "The Prince and The Showgirl" with Olivier.

Simon Curtis serves as director for "My Week with Marilyn" with the script written by Adrian Hodges. The biopic has just completed filming at Pinewood Studios in England and is expected to grace theaters in 2011.